Influence of municipal and industrial pollution on the diversity and the structure of benthic macro-invertebrates community of an urban river in Douala-Cameroon (Central-Africa)
By: Onana Fils Mamert, Zébazé Togouet Serge Hubert, Koji Ernest, Nyamsi Tchatcho Nectaire Lié, Tchakonté Siméon
Key Words: Benthic macro-invertebrates community structure, Municipal and industrial pollutions, Water quality, Bio-indicator, Cameroon.
J. Bio. Env. Sci. 8(6), 120-133, June 2016.
In the harbor city of Douala, urban land use has increased dramatically over years, resulting in high variability in aquatic ecosystems. In this study, we used benthic macro-invertebrates community structure to assess the impact of urban pollution on the aquatic health of an urban stream in Douala township. Samples were done monthly, from April 2011 to May 2012 in three sampling stations located on the watercourse Kondi and named K1, K2, and K3. Benthic macro-invertebrates were collected using a long-handled net (30 cm x 30 cm side, 400 µm mesh-size). Measurements of the environmental variables were done simultaneously. Physico-chemical analysis revealed the very poor health status of the Kondi stream with highly polluted water at station K2, which received the effluent of the Cameroon SABC brewery. A total of 2,258 individuals of benthic macro-invertebrates distributed into 28 families were identified. This macrofauna is dominated in the Kondi stream by pollution resistant taxa such as Chironomidae (21.70%) and Physidae (24.05%). Diversity indices, taxonomic richness, total abundance and relative abundance of insects were high in stations K1 and K3, revealing their slightly high diversity. These two stations receive mainly domestic wastes. Inversely, in station K2 which receives industrial and municipal effluents, benthic fauna is less diversified, with low diversity indices, lost of sensitive taxa, decrease of the abundance of aquatic insects. The results obtained in this study showed that bad management of municipal and industrial effluents contributes to degrade the water quality and to reduce biodiversity of benthic macro-invertebrates.